INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Vol. 10, No. 4, pp. 5-12 OCTOBER 2009 / 5 DOI 10.1007/s12541-009-0065-5 1. Introduction Conventional five-axis machining has been applied mainly to machining turbine blades, 1 impellers, 2 and marine propellers 3 by specialized machines. In addition, the mold and die manufacturing industry is eager to apply five-axis machining to reduce lead time and enhance surface quality. 4,5 A typical marine propeller for a large ship has these features: four to six blades, diameter to 10 m, maximum weight over 10 tons, and made of copper alloy. It is manufactured by a series of processes such as casting, numerical control (NC) machining, and manual grinding (see Fig. 1) by a domestic ship building company. Fig. 1 Propeller manufacturing process The NC machining process has distinct stages: three-axis profile machining, five-axis face milling along a curve on the blade surface (roughing), five-axis face milling along isoparametric curves on the blade surface (finishing), and a few additional five- axis face milling stages, all of which are conducted on a dedicated five-axis NC machine that has a specialized kinematic structure. In addition, a large face milling cutter (250 mm diameter) is used for high cutting efficiency and surface quality. Figure 2 depicts sample blade surfaces and milling tool paths. Fig. 2 Blade surfaces and milling tool paths A study to generate five-axis CL (cutter location) data for face milling of large marine propellers was performed. 3 Cusp height between two consecutive paths was calculated, and the C-space (configuration space) concept was adopted. For the past decade, Near Net-Shape Five-axis Face Milling of Marine Propellers Jung-Whan Park 1,# , Jung-Geun Lee 2 and Cha-Soo Jun 3 1 School of Mechanical Engineering, Yeungnam University, 214-1, Dae-dong, Kyoungsan, South Korea, 712-749 2 WillTech., 214-1, Dae-dong, Kyoungsan, South Korea, 712-749 3 School of Industrial and Systems Engineering, Engineering Research Institute, Gyeongsang National University, 900, Gajwa-dong, Jinju, South Korea, 660-701 # Corresponding Author / E-mail: jwpark@yu.ac.kr, TEL: +82-53-810-3524, FAX: +82-53-810-4627 KEYWORDS: Marine propeller, Five-axis machining, Optimal tool position We present an optimal cutter location (CL) data computation for face-milling of large marine propellers composed of CL point optimization and CL path optimization on a given tool path. The CL point optimization at a single cutter contact (CC) point is conducted by maximizing the effective radius of the face milling cutter, while the CL path optimization on a series of CC points is performed by conforming deviation of the tool-swept surface from the design surface between consecutive CL data to a given machining tolerance. The proposed algorithm was implemented and applied to the machining of a large marine propeller which proved effective from a quantitative point of view, and is used on the shop floor in a Korean ship building company. Manuscript received: September 26, 2008 / Accepted: May 9, 2009 © KSPE and Springer 2009